My son has driven his 06 Cobalt SS/SC to 165,000 miles . The timing chain finally jumped and bent all 8 intake valves. My problem is both bolts on the black chain guide have broken , and where the lower timing chain guide was mounted it has worn a groove in the aluminum mounting boss .. like the one in this thread ..

https://www.cobaltss.net/forums/2-0l...ailure-290968/

ours is a little more chewed up then the one in the pic !

How is the best way to repair this with the engine still in the car ?

What has anyone done ?

Thanks, SIKPUP

 

post a pic up of the damage

 

I haven't learned this site yet . I was able to get it as a signature picture in my profile. Sill working on how to post a pic. Picture shown is our block !

Thanks , SIKPUP

 

Create a photobucket account and put the pics on there. Copy the IMG line and post up here.

 

 

 

 

[IMG][/IMG]

 

Grind it flush then use a washer to back space the black guide forward the amount you ground flush.

New bolt with loctite also

 

do what jap said but look down the chain from the valve cover to make sure the chain runs center of the chain guide

 

This^^

Also in order to get the thickness of the washer just right you may need to do some additional fitment

I would run a tap thru the threads to chase it as well

 

My concern is that it is worn a lot deeper then it looks ! I don't think the stock bolt will be threaded deep enough to catch enough threads. I may need to find a stud with a spacer that fits to have the adjustability to line the guide up with the chain. Has anyone used some kind of aluminum epoxy to fill that "pothole" back to original surface level ?

 

qwick steel will work. you can also drill and retap it deeper as well

 

**** quick steel its a half ass fix that can break out easily

either get a used engine or pull that engine and remove the broken and get the damage welded up flattened out and tapped

 

truth

 

The shoulder on the guide bolts r 11.5mm a really odd size.

Buy yourself a 12mm hand reamer. Then a 12mm sholder bolt with a m6x1.00 thread on it with the proper threat length the tale up the difference.

 

True story bud, just replaced my motor for the same situation... I wouldn't cut corners Mr. B is absolutely correct.. Good luck sir.

 

B4 u scrap the block try to grind it flush

 

First I'm going to lower the engine cradle on the pass side, and if I need more room I will trim the pinch weld. I'm going to drill the broken bolt out with left handed bits. To see where I'm at. Has anybody TIG welded the block ? With it in the car ? Can a longer stainless steel bolt be threaded into the hole and be tigged around it ? retapped and ground smooth ?

All opinions welcome ! Only have one good chance to fix it ? Want to figure the best option before doing something non repairable....

Thanks, SIKPUP

 

I have tigged the timing cover while on the car, not the block itself

I think u have better luck with grinding it smooth and backspacing the guide, drill and tap to M6 x 1.25

 

You know it is pretty fuked gm hooks us up with bolts that snap from timing chain guide rails.. Tbh I haven't heard of any other cars with this issue.. Only the cobalt.. Am I mistaking lol??

 

the easiest way to get the broken bolt out it to weld a nut to the broken off bolt and unscrew

 

So my 2006 Cobalt ss 2.0 Lsj died on me a few days ago. Opened up the front cover cause there was a bunch of timing codes and same thing. Chain guide rail is broken. The upper bolt head, lower bolt and piece of rail are probably in the oil pan. Lower bolt hole boss is hallowed out and I need to extract the upper ones bolt shaft. Was wondering which is the best route to take, buy a new engine or try to repair?